Hi Chris,
I speak German but my electronical knowledge is very bad. So, what is better?
Regards
Tolu
I speak German but my electronical knowledge is very bad. So, what is better?
Regards
Tolu
Maybe in your language,...in portuguese means fool
We write "tolo"...but we pronunciate "tolu"
Well.... only Portuguese speaking people will read this way...not more than 400 million people, as it is the 5 language in the world in quantity of speakers.
Be happy my friend Tolu, and please, have fun with us.
regards,
Carlos
We write "tolo"...but we pronunciate "tolu"
Well.... only Portuguese speaking people will read this way...not more than 400 million people, as it is the 5 language in the world in quantity of speakers.
Be happy my friend Tolu, and please, have fun with us.
regards,
Carlos
And I want to know,🙂 about biasing Symasaym in class A (or AB)I know it was written in this thread before about it(Looong thread)anyone done any long term test with high bias,how much ,result?
You mean,turn up the bias,messaure the the temp on the heat sink to 60degres...
NO,if I only want about 2-5w in class A,how much over the emitter resistor?Can I use this ClassA calculator
Hi !!
As I already said, I love symasym, and I'm searching for little more power on it.
The original Symasym use MPSA18 transistors, that the maximum suported voltage is 45v. Also use the low voltage BC546.
All other transistors are high voltage rating, the lowest one is the BD139, that is 80v.
So, swapping the MPSA18 with the MPSA42, and the BC546 by the 2n5551 (pins reversed), can I power the Symasym with + - 56v supply rails ?
The idea is swap the low voltage rating transistors with higher ones, and replace the needed resistors, to achieve more power (56v rails), without modify the original symasym design. Is it possible?
Thanks !!
As I already said, I love symasym, and I'm searching for little more power on it.
The original Symasym use MPSA18 transistors, that the maximum suported voltage is 45v. Also use the low voltage BC546.
All other transistors are high voltage rating, the lowest one is the BD139, that is 80v.
So, swapping the MPSA18 with the MPSA42, and the BC546 by the 2n5551 (pins reversed), can I power the Symasym with + - 56v supply rails ?
The idea is swap the low voltage rating transistors with higher ones, and replace the needed resistors, to achieve more power (56v rails), without modify the original symasym design. Is it possible?
Thanks !!
HI
I have the same question to , I would like to get out a bit more power from my Symasym . I have a transformer 2x40V 500VA . It would be around 56V DC ..
I would like to keep it simple so I would stick with one set of power transistors design .
I belive the drivers will be OK to but I'm not sure about the small transistors .
Did some run the Symasym from 56V power supply . Any advise , help etc please .
Regards
I have the same question to , I would like to get out a bit more power from my Symasym . I have a transformer 2x40V 500VA . It would be around 56V DC ..
I would like to keep it simple so I would stick with one set of power transistors design .
I belive the drivers will be OK to but I'm not sure about the small transistors .
Did some run the Symasym from 56V power supply . Any advise , help etc please .
Regards
Not really a good idea.
SymAsym with one pair of output devices doesn't have much headroom for additional power. You would have to change the small signal transisitors for higher voltage parts (e.g. 2N5551/2N5401), but the output stage can't deliver much more power than in Mike's original design.
You might be able to run high impedance speakers, but nothing else.
SymAsym with one pair of output devices doesn't have much headroom for additional power. You would have to change the small signal transisitors for higher voltage parts (e.g. 2N5551/2N5401), but the output stage can't deliver much more power than in Mike's original design.
You might be able to run high impedance speakers, but nothing else.
PMA said:
With their 80v rating they wouldn't survive +/-56V... 😉
But, inreasing vas-current is a redesign, as the whole fb compensation stuff needs to be redone!
Mike
MikeB said:
80V - yes, I know 😉
Regarding compensation and stability - this is a bit Achilles' heel of the symasym. Even an original design does not exhibit a plenty of stability margin ... 😉
I am now to finish a development of a new amp, similar output power as symasym. I can load it by 3.3uF in parallel with load resistor and no stability problem occurs. MOSFET output stage, these devices withstand a lot ..
finally gave it symasym a try. just grabbed the gerbers off the site and fabbed as not much more to have some made than for me to reload on etchant and copper etc, plus i hate the drilling. probably unload the remainders.
nice sounding, i like the clearness and transparency. bass clean and defined. not slamming my speakers low end but very good quality sound and goes deep as needed.
thanks mikeb
nice sounding, i like the clearness and transparency. bass clean and defined. not slamming my speakers low end but very good quality sound and goes deep as needed.
thanks mikeb
